Lease Addendum Template (Free PDF & Word) for Landlords and Tenants

Adding a pet, changing a rent due date, or bringing on a roommate shouldn't mean tearing up the entire lease. A lease addendum template lets landlords and tenants add or adjust specific terms while keeping the original lease agreement intact. Below is a free, downloadable lease addendum template, plus a step-by-step guide for filling it out and knowing when to use one.

What Is a Lease Addendum?

A lease addendum is a legally binding document that adds terms, rules, or disclosures to an active lease agreement.

Unlike a new lease, an addendum works alongside the original agreement. Once all required parties sign it, the addendum becomes part of the lease. It has the same legal effect as the rest of the agreement, provided it complies with applicable law. If a provision in the addendum conflicts with the original lease, the later signed addendum generally controls to the extent permitted by law.

For example, a landlord may use a lease addendum form to:

• Allow a tenant to keep a pet
• Add a new roommate
• Update parking assignments
• Introduce new property rules
• Add utility or storage provisions
• Permit installation of satellite equipment or EV charging devices where applicable

(Note: If the parties need to change an existing lease term—such as the rent amount, payment due date, or lease expiration date—they will often use a lease amendment or, if extending the tenancy, a lease renewal. If you're planning to renew a tenancy instead of creating a new lease, our guide to writing a lease renewal letter explains the process and what information to include.) 

Property managers and independent landlords rely on lease addenda to address changing property needs without drafting an entirely new lease. For example, if a tenant requests permission to keep a dog in a previously no-pets rental, both parties can sign a pet addendum outlining approved pets, applicable fees (where permitted), and the tenant's responsibilities.  

Free Lease Addendum Template [Download]

Below is a free, editable lease addendum template. It adds terms to an existing lease without drafting a new one. It comes as a fillable Word document and a print-ready PDF — choose whichever format fits the workflow.

Sample Lease Addendum Form

How to Fill Out and Execute a Lease Addendum (Step-by-Step)

Executing a lease addendum requires careful attention to legal references and consent from all involved parties. A clear, systematic process helps the new terms hold up in court if a legal dispute arises.

Step 1: Identify the specific term or policy to add

Start by identifying the exact lease term, property rule, or responsibility that needs to be added or clarified. Most mid-tenancy modifications—such as allowing a pet, adding a roommate, or updating smoking policies—should be clearly defined before drafting the addendum to avoid confusion or conflicting interpretations.

For a pet addendum, specify any pet fees (where permitted), breed or weight restrictions, and the tenant's responsibility for pet-related damage. For a smoking addendum, define where smoking or vaping is prohibited and whether any designated smoking areas exist.

Step 2: Reference the original lease details accurately

List the exact lease date, property address, and full names of all parties as written on the original contract. An addendum to a lease agreement must match the primary lease details exactly. If the original contract lists "123 Main Street, Suite 4B," copy that exact address to avoid enforcement issues.

Step 3: Draft the new terms in plain, specific language 

Write clear conditions and avoid vague wording. Clearly describe the new terms, each party's responsibilities, any payment changes, and any conditions that apply. If your addendum takes effect on a future date, state the effective date clearly. If you draft a roommate addendum, explain whether all tenants share responsibility for rent and other lease obligations. To create consistent legal documents, review our library of lease agreement templates.

Step 4: Review with the tenant/landlord before signing

Provide the draft document to all legal parties for complete review prior to obtaining final signatures. 

In most situations, landlords cannot unilaterally change the terms of an existing fixed-term lease unless the original lease allows it or the change is required by law. Both the landlord and tenant should review the addendum, ask questions if needed, and voluntarily agree to the new terms before signing. 

Step 5: Sign, date, and attach to the original lease file

Collect signatures from every original lease signer and property owner. Utilize secure electronic signature (eSign) technology or physical ink signatures to sign the form. Once executed, provide a signed copy to the tenant and archive the original document in your property management software or physical filing cabinet. To streamline your document workflow online, consider using an online rental contract platform. 

When Do You Need a Lease Addendum?

You need a lease addendum whenever you adjust or clarify rules during an active tenancy without ending the current contract. Landlords and tenants rely on lease addenda for various legal and operational updates throughout a tenancy:

• Pet Addendum: Defines approved pets, pet fees or deposits (where permitted), breed or weight restrictions, and the tenant's responsibility for pet-related damage.
• Roommate Addendum: Formally adds or removes an adult occupant from the lease. It often includes a joint and several liability clause, meaning each tenant is individually responsible for the full rent and for complying with all lease terms, regardless of how roommates divide payments.
• Smoking Addendum: Establishes rules regarding smoking or vaping inside the rental unit, on balconies, or in common areas. Some landlords also address cannabis use where permitted by state law while complying with applicable fair housing requirements.
• Parking Addendum: Documents assigned parking spaces, guest parking rules, towing policies, or the use of garages and storage areas.
• Utility Addendum: Clarifies responsibility for utility payments, billing methods, or changes to utility services not addressed in the original lease.
• Property-Specific Addenda: Documents agreed rules for amenities, security systems, smart home devices, guest policies, or other property-specific requirements.

A lease addendum is not the right document for every situation. If a landlord needs to end a tenancy, an eviction notice or lease termination letter is generally the appropriate document instead. Likewise, certain legally required disclosures—such as the federal Lead-Based Paint Disclosure for housing built before 1978—are typically provided as separate disclosure forms because they have their own content, signature, and timing requirements.  

Conclusion

A lease addendum template is a key tool for landlords and property managers. It lets them update rental policies while keeping a clear, legal framework in place. Get the original contract's dates right. Draft explicit terms. Collect every required signature. Do this, and housing providers protect their investment while keeping tenants fully informed.

LeaseRunner helps landlords manage leases, addenda, and tenant screening from one place, with state-specific templates and built-in e-signature support to keep every change properly documented. 

FAQs

1. What is the difference between a lease addendum and a lease amendment?

A lease addendum adds new rules or details that were not originally addressed in the contract (e.g., adding a pet policy or parking rules). A lease amendment modifies, deletes, or updates terms already present in the original agreement (e.g., changing the rent due date, extending the lease term, or adjusting the rent amount). 

If the change involves increasing rent, landlords may also need to provide a rent increase letter, and should first verify how much can the landlord raise rent under applicable state or local law. Both legal mechanisms require mutual written consent and signatures from all parties to be enforceable. 

2. Can a tenant refuse to sign a lease addendum?

Yes. A tenant can refuse to sign an addendum during a fixed-term lease if it introduces unnegotiated rules or costs. Landlords cannot force mid-term changes unless the original lease or local law allows them. If the tenant refuses, original terms remain active until the lease expires.

3. Can you add a lease addendum after the lease is signed?

Yes, you can add a lease addendum after the lease is signed, provided both the landlord and tenant agree to the updated terms in writing.

Once a lease is signed, any subsequent changes require mutual consent. To modify rental agreement without a new lease, both parties must sign the new lease addendum form, which is then attached to the master agreement. 

4. What happens if someone violates a lease addendum?

Violating an addendum carries the same legal consequences as breaking the main lease. Because the document is legally binding, a breach—like bringing an unauthorized dog under a signed pet addendum—allows the landlord to issue a cure-or-quit notice or start eviction proceedings.

Disclaimer: The information provided in this post is intended for general informational and educational purposes only. It should not be construed as legal, accounting, or tax advice. For guidance specific to your situation, we recommend consulting with a qualified professional in the relevant field before taking any action based on the content provided.